Please could you explain to me, if Squirrel is "similar to Lua, but uses a C like syntax", why I wouldn't want to use C or Lua instead? Is this about Steam? If not, is this (even) faster than Lua? Is it easier or safer than C? Am I missing something? You better have something seriously good to offer if in your first breath you're pitching yourself alongside the very best of both interpreted and compiled languages.
The remaining differences seem pretty minor; IMO having the OO system baked into the language instead of implemented in user-space is a step backwards. The 0-indexing might be nice if you do a lot of FFI with C, I suppose. Hardly worth giving up the insane performance of LuaJIT for though.