Marble Ultra, not exactly a great game really.
Most of the Live Arcade games aren't anything specutacular yet, because over half are just ports.
(most of which are from the mid-80s)
a big problem for independant developers for 360 creation is the high-quality the games developed must be.
it's not like the PC where you can release and if there are bugs and glitches you can always fix them later... it's not that you can't release a patch but the certification process requires them to be practically bug-free from the get go.
What's more is in order for you to test on the 360 it requires you to have a special 360 while developing, this in-turn requires EACH concept to be written off by Microsoft. If they don't approve it, then you can't get the hardware. No Hardware = potencial certification issues.
The hardware also isn't cheap, or in abundant supply.
I mean it looks cool on the surface that something like this happened, but remember Garage Games aren't new to the "arcade" title market. All they did was port a game they released for the PC with their 360 middleware engine; in order to have created that engine they would've been using full development hardware (not just cheap reviewer kits) plus they get quite a bit from their middleware.
They do make far more than most indie middleware companies. Remember they've also had several retail released game that use their engine.
I'm far more impressed by Totemball tbh, as it was developed by an independant English developer as the only Live Video game available on live. More impressively by only 2 guys.