Compatibility, Game Modes & Rollback Netplay
Measured playability across Smash modes, 13.0.5 DLC fighters, Quickplay & Battle Arenas, SSBU_RB rollback frame timings, and experimental Linux/macOS builds.
- 13.0.5 full DLC roster
- 1v1 Rollback default
- EU & NA 39421 lobbies
- Cross-play Win & Linux
Game modes, roster & platform compatibility matrix
Unified OpenSmash-Ultimate/OpenSmash-Ultimate targets Super Smash Bros. Ultimate version 13.0.5 exclusively, meaning every base fighter, stage, balance patch, and owned DLC fighter up through Fighters Pass Vol. 2 (Kazuya and Sora) shares a single deterministic simulation binary:
| Mode / Platform | Current Status | Measured Upstream Notes |
|---|---|---|
| Boot, Opening Movie (VP9) & Menus | Playable | Full 60 FPS menu navigation, Opus BGM, and VP9 cutscenes via bundled libopus / libvpx or FFmpeg. |
| Smash (Local 1v1 & up to 8 Players) | Playable | Complete matches through the results screen across base + all 13.0.5 DLC fighters (up to Kazuya & Sora). |
| Online → Quickplay (1v1 Rollback) | Active (Default Rollback) | Matches against the community NEX game server (port 39421) with SSBU_RB rollback on by default in v0.3.0-alpha.3 and GSP tracking. |
| Online → Battle Arenas | Experimental | Create Arena, Advanced Search, waiting ring tokens, and 2-player rollback fights work on the 39421 server; 3–4p and Arena ID/password search still in testing. |
| Local Wireless (Public Lobby, Code & LAN) | Playable | Up to 24-room paging, Netplay v3 Room Browser & mod-diff view, UDP hole punching, 1v1 rollback, and zero-config LAN multicast (239.255.13.13:39501). |
| Training, Classic Mode & Home-Run Contest | Playable | Verified starting and playing through matches; run-ahead and savestate infrastructure built into runtime. |
| Spirits, Vault Album & Mii Fighters | Reachable / Working | In-game pause snapshots save as album/*.bmp; up to 100 custom Miis load from miis/*.charinfo. |
| Adventure (World of Light) & Replay Video Export | Partial / Unsupported | World of Light intro reached (full map/fights not yet audited); converting saved replays into video files is not yet implemented. |
| Linux x86-64 (DXVK) & macOS (Apple silicon Metal) | Experimental | Linux builds run matches and cross-platform lobbies with Windows; macOS 14.5+ verified at 60 FPS through menus and character/stage select on M-series chips. |
Online multiplayer architecture: Lobbies, Quickplay & LAN
OpenSmash-Ultimate never touches Nintendo’s servers. Instead, OpenSmash.exe connects to lightweight community Python servers (tools/ssbu_online_lobby.py on TCP+UDP port 39421, or legacy relay-only port 39420):
- Automatic fastest regional lobby (
online_server.txt=auto): At launch, the client times a handshake to Europe (opensmash-lobby.duckdns.org:39421) and North America (smash.recomps.wtf:39421) and joins whichever responds faster (pin manually witheuorna). - Direct P2P UDP hole punching (#139): Once two players enter a Local Wireless room, the lobby introduces them and opens a direct UDP path even across symmetric NAT routers via port learning, UPnP / NAT-PMP / PCP, and sequential port prediction. Press F1 to verify
direct 12 msvsrelayed. - Netplay v3 Room Browser (#122): Setting Netplay version = 3 in Esc → Online enables the Lobby tab (5), listing up to 30 rooms per page, showing why incompatible rooms cannot be joined (version or exact mod list mismatch), and pinning your chosen room to the top of Local Wireless → Rooms List.
- Zero-address LAN discovery: On a home router or local venue network, one PC hosts via
Host SSBU Netplay.bat(announcing over UDP multicast239.255.13.13:39501) while other PCs set Play online in → this network (LAN) to join automatically within 1.5 seconds.
Measured SSBU_RB rollback netcode benchmarks
In 1v1 Quickplay, 2-player Battle Arenas, and 1v1 Local Wireless rooms, both games negotiate SSBU_RB rollback within 15 seconds (3- and 4-player free-for-alls fall back automatically to standard delay netcode). Because a 60 FPS frame budget is 16.7 ms, any rollback catch-up under 16.7 ms is completely invisible:
| Round-Trip Ping | Input Delay | Rollbacks (3-min Match) | Frames Re-run | Catch-Up Time (Mean / Worst) | End-of-Fight State Hash |
|---|---|---|---|---|---|
| ~1 ms (Same PC / loopback) | 1 frame (auto) | 1–6 | 2 frames | 7–10 ms | Identical |
| ~40 ms (Live 2-PC match) | 2 frames (floor) | 15 across 2 fights | 2 frames | < 16.7 ms (locked 60 FPS) | Identical |
| ~65 ms (Simulated RTT) | 1–2 frames | 800–1,200 (bot stress) | 2–3 frames | 11–12 ms (27 ms worst) | Identical |
| ~115 ms (Cross-region) | 2 frames (auto) | 790–1,280 (bot stress) | 2–3 frames | 13–15 ms (41 ms worst) | Identical |
| 120–150 ms one-way | 6–9 frames (auto cap 9) | High-ping fallback | 3–5 frames | < 5% catch-ups over 16.7 ms at delay 7 | Identical |
If two clients ever diverge or a peer disconnects for 8 seconds, OpenSmash alerts you cleanly and writes reports\rollback_<date>_<time>.txt for bug reporting.
Current known visual & workflow limitations
- Blue KO finish zoom: As noted in the
v0.3.0-alpha.1andv0.3.0-alpha.2release notes, the red screen-flash zoom on match-ending KOs currently renders blue instead of red. - Intel Iris Xe Vulkan driver bug: Tracked in GitHub Issues
#333,#346, and#327; work around immediately by switchingrenderer = direct3d11inconfig\display.ini. - Adding new DLC after initial build: Tracked in Issue
#340; place newly dumped DLC packages next to your 13.0.5 game files and re-run setup /build_game.pysodump/modules/aoc.cfgand DLC fighter NROs update.
Smash PC controllers & adapters
OpenSmash-Ultimate and WindowSmash support up to 8 concurrent players via SDL3, XInput, and native Wii U / Switch GameCube USB adapter polling (both Windows HID and Zadig WinUSB drivers, with analog L/R triggers and rumble):
| Hardware | Best For in OpenSmash-Ultimate | Input Path & Latency Notes | Link |
|---|---|---|---|
| Mayflash 4-Port GameCube Controller USB Adapter | 4-port GameCube controller play | Switch to Wii U mode for native 4-port GameCube input + rumble (second grey USB plug) | View on Amazon |
| Nintendo Switch Pro Controller | Native positional ABXY layout | Matches Switch button positions out of the box via SDL3 (`[device switchpro]`) | View on Amazon |
| GameSir Cyclone 2 | Low-latency 1000 Hz wireless Smash | Zero-drift TMR sticks, microswitch face buttons, XInput & Switch SDL3 modes | View on Amazon |
| 8BitDo Ultimate 2 Wireless | Desktop & SteamOS handheld dock | TMR sticks, charging dock, 2.4 GHz dongle + Switch / XInput mode switch | View on Amazon |
| Sony DualSense | PlayStation pad (`[device ps5]`) | Full SDL3 support with configurable per-device rumble and deadzone in `controllers.ini` | View on Amazon |
| Xbox Wireless Controller | Zero-setup Windows 10/11 XInput | Works natively for players 1–4; set `layout = labels` or `style = gamecube` if desired | View on Amazon |
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Common questions
Can Windows and Linux players fight each other online?
Yes. Both Windows (OpenSmash.exe) and Linux (play-ssbu.sh / run.sh) compile from the exact same 13.0.5 C translation and speak the same lobby and Local Wireless protocol.
How do I disable rollback netcode if I want to test standard netplay?
Press Esc in-game, go to Online → Rollback netcode, and switch it to off (which writes off to online_rollback.txt on next start), or launch with environment variable SSBU_RB=0.
Can a tournament or Discord community host its own private lobby server?
Yes. Run python tools/ssbu_online_lobby.py --port 39421 --state online-state --verbose (requires Python 3.8+ and TCP+UDP port 39421, plus UDP 39431 for NAT hole-punching; zero game files required on the server).