Heaping Tablespoon

Insular Gigantism

Beyond Measure

Break Infinity

Rather large lock

Dolphiner's Lament

Gave it one poke at it, but I can already see the structure is really tight and cool. Gorgeous design.

The best possible 5x5 construction you will ever see. The construction is just genius.

The 2-off is very very annoying.

wtf man

EDIT: After having solved R4, it became much easier to understand the kind of deductions you need to be able to reach the exit, but it is still not easy or trivial. Optimization, while not brutally evil, is much more involved than the optimization of R4.

Unknown Arena #15

The structure is actually very cool but the aesthetic is ???