The Mini Bros game is 2.5 kilobytes of high level source[1] so a fair resource comparison should either include FastBasic 3.4's runtime footprint (if interpreted?) and/or a compiled standalone executable size (if FastBasic is capable of it). i.e. ROM + RAM requirements to run on bare metal, including libary/runtime dependencies.
But my byte-counting pedantry aside ;-), you're exactly right to celebrate authors of such tight works that are still actually fun and attractive. I enjoyed the author's line-by-line walkthrough and dev journal. I know some modern programmers may not see the point in these apparently arbitrary competitions targeting old platforms but I really think there is wisdom and magic in this frugality!
[1] https://www.dropbox.com/sh/zj7u96etduyq6bv/AABfTzwMu3pqoNSNA...