Clocks are fine for restoring time, I would just have them restore less, maybe 50% of the current bar or just 25% of the total bar. But right now they show up a LOT. I got 3 back-to-back during one game! And hourglasses were coming rather frequently as well. The bulk of the game should be fish and mines, and when you see a clock or an hourglass you make every effort to pick them up. I never had an issue with running out of time, I stopped playing because I felt like I had seen everything the game was going to show me. I think if you make the clock and the hourglass have an equal % of generating, and maybe split the rest between the mine and the fish, you might have something. Say 30% fish, 40% mine, 15% clock, 15% hourglass. Not sure if that makes the hourglass and clock show up too often, but those are the kinds of ratios I think might work.
The only speed increase I see in is the movement of the play field, I don't see the mines or fish coming any faster than usual, just one right after another.
Is it possible to add "safe spots" where the Walrus can land and catch his breath a minute? (I'm now thinking about the video you linked to), or other kinds of enemies to dodge?
Your Walrus makes the SNES walrus in the video look silly. Hooray for VCS Walrus!
I love the concept and the visuals are great! Keep up the great work!