Recent reviews by Procedural Texture

First impression: this game is not as fun as it appears. It's far, far better.

I've seen better implementations of this genre on 8-bit machines. Unplayably bad.

Positives:

Though still in need of some refinement and balancing—and possibly some additional features—the core gameplay of Mini Metro scratches that city-building itch without requiring a major investment of time. You can play this on a break without worrying you'll be sucked in for hours (though you won't get bored if you did waste a day on it).

The interface is a case study in complex, context-sensitive functionality from simple interactions. Click, hover, drag and drag paths all combine to do just what you want without requiring a tutorial. Though you might spend your first game puzzling it out, it all just works how you'd expect on the first or second try. Pure, blissful affordance. If only more games thought out their interface so elegantly.

Negatives:

There is a well-known "cheat" that isn't really a cheat (it's inherent in the game rules) but that renders the leaderboards meaningless. The devs are still struggling with this issue, and I think it's resolution must lie in clarifying the game's biggest ambiguity: am I running a simulation of a real subway network (in which case, shouldn't it cost me something to re-route lines) or am I stress-testing a subway plan by iterative design under increasing load (in which case, shouldn't I have some prior information about where additional stations will appear). This ambiguity is at the heart of the game's ultimate success or failure, and the devs need to do more than apply band-aid solutions and ad hoc rule tweaks. I feel like the solution is to split the game into entirely different game modes which rest on different existential assumptions about what the game really is.

A little more information and clarity, compactly presented, would reduce some of the minor frustrations and provide greater insight into the network you've built. How many trains do I have on a given subway line? Can I see some meaningful data on throughput or efficiency? I have trouble believing the devs haven't read any of Edward Tufte's masterful works on data presentation. They'd do well to revisit his books for ideas.

[REVISED] The passenger AI is improving. Rather than being deterministically stubborn, passengers have acquired a variability that sometimes even includes whimsical train hopping in the wrong direction and then back again. This is an improvement. There's often more than one way from A to B, not to mention that sometimes B2 or B3 offer variety. It's slightly mad, but it's better than robots.

Some other minor complaints:
- why am I limited to 4 trains per line? Couldn't that limit be a function of the line's length and/or the number of stations?
- why can't a line go around a river bend rather than cutting the corner and requiring a tunnel?
- why no save feature? sometimes I'm having a very successful game, but I have to get back to work, or join friends in another game

TL;DR:

Enjoyable game. Can be played casually or obsessively. Brilliant with the potential to be an all-time classic. Well worth full price. It would be criminal to wait for a sale price.

This little game is a great value on its own merits. It's just that its sequel (Fortix 2) is so much vastly better in every respect—enemy variety, level design, graphics, music and overall polish—that there's no point in buying the original if you already have the second generation. You won't regret buying this game, but it's been made redundant.

Highly recommended. A knights and dragons twist on the old Qix game mechanic, with tower defense thrown in for good measure and plenty of other interesting variables. Tactical complexity for a very simple concept. Much replay value.