After playing through the full game for the first time, it reminds me more of Super Mario Land 1 than anything. Like that game, and unlike Super Mario Bros. 1, every level has a semi-unique visual theme and gamefeel—as long as you ignore the desert levels, which all pull from the same dreadful bucket of enemies and gimmicks.

The collision is really bad. The shrunken player appears to be about a tile tall but is actually a bit over, even while crouching; maybe a third of the hits I took came from stuff that looked like it should've gone over my head (Birdo eggs, etc.). Also, projectiles that bounce off walls are still quite alive, despite looking dead (and, in other games, being dead). And for some reason, I kept getting wedged into walls. I could just jump out, but it was a bit distracting. Pretty buggy by Mario standards!

Beat with warps and continues (but no cheats, and I beat every level at least once).

Beat over the course of an evening, with no Warp Zones or savestates but ample continues.

My problem with SMB1 has always been that Mario doesn't control like Mario—he has the moves, but they come with much more inertia than in later games, especially in the air, and he sometimes accelerates at weird times. The result is physics that are OK for a platformer but pretty bad for the series.

Despite the limited engine and relatively small enemy and object palettes, the game is varied enough; no two levels feel the same, and most of them are fun. The infamous Cheep-Cheep Bridge was much easier than I expected (only one death across multiple continues), but 8-3 was absolutely dreadful—a whole level built around the worst enemy in the game! World 8's levels felt a bit long in the tooth in general, and not just because they ate over a dozen continues.

I wish someone had warned me that the continue cheat restarts you at the beginning of the current world.