I think it's difficult for us to comment on the difficulty curve, being pros of the genre. It does seem to to find clever ways to let the player figure things out for the first time, like a scroll in the proper location to scare out a roach queen in the third level.
One quick gripe (and this is because I'm a spoiled DRODiac) about the secrets. For starters, when you find a secret, it shifts your minimap in the direction of the room, cutting off an entire row or column. I'm assuming all levels will be 5x5, right?
Also, collecting secrets doesn't seem to be done in the same fashion as it seems in DROD. I found the secret in level 1, increasing my counter to 1/25. Then I played until level 4. Then I restored back to level 2 and found that secret. Now, when I restore to the room the secret is attached to in level 2, it says I've collected 2/25 secrets, but if I restore anywhere in level 3 or 4, my counter drops back down to 1/25. This forces the player to find all of the secrets properly the first time through if they ever hope to score 25/25. DROD secrets are always cumulative, regardless of the restore state, and that eliminates the need to replay entire levels.
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