From the page content excerpted in the source, TinyAIArena presents a spectator/replay-style interface: it includes buttons such as MENU, PREV, NEXT, AUTO PLAY, NEW GAME, as well as GAME LOG and GLOBAL CHAT areas; the status shows "Frame 0 / 0" and "Pre-game", the audio status shows "SOUND: ON", and the page also displays "Loading assets…".
The interaction hints state that you can use left/right arrow keys, Home/End, spacebar for auto play, Esc for menu, and M for mute. The page code comments also mention that ui/ArenaHud.ts is responsible for populating text and wiring up buttons, and that the parent is created once at startup and never replaced.
These details show that the interface skeleton exists, but they describe "how to operate" and "how to render", not "how the battle proceeds".