For the most part, Zach Gage's iOS output has been about subversion - subtle twists on entrenched genres.

The results have often been simple, boasting an immediacy but not necessarily the kind of initially manic addictive qualities associated with the very best iOS titles.

And then you realise with a shock that his latest game was all you'd been playing since you last remembered to eat about a week ago.

Sage Solitaire's another such creation, taking one of the biggest videogame time-wasters of the desktop era - Solitaire - and reimagining it for mobile screens in portrait.

One of a kind

The aim remains to dispose of every card on the board, but the layout is now a three-by-three grid, and there's no shifting cards from place to place, nor any need to dutifully file them away in order and by suit.

Instead, rules are borrowed from poker, with you tapping out hands (three of a kind, flush, full house, and so on) to remove cards and work your way through the piles.

Further strategy comes in various forms. Using at least one card from a starred suit (randomly picked at the start of each game) doubles a hand's score.

Remove one of the nine piles entirely and you get bonus points - 150, 100, or 50, depending on whether the cards were on the top, middle or bottom row.

Trashes enable you to remove a card without playing a hand, but you only get two. One replenishes with each successful hand. And finally there's the requirement that any played hand must include a card from at least two rows.

Suits you

At first, Sage Solitaire is easy to dismiss. It seems quite throwaway - the sort of title you might happily dig out when waiting for a bus, but not something you'd play for hours, fighting for a high score.

But then something clicks. The combination of the aforementioned subtle strategic elements makes for a much deeper game than you might have initially realised.

Two additional modes accessed through a one-off IAP provide slight variations on the theme - two decks, or the means to also remove cards that add up to 15 - and with them comes the need to devise further unique and increasingly smart strategies if you want to reach lofty heights in Game Center.

It's hard to know a couple of weeks in whether Sage Solitaire will have the staying power of the likes of Gage's SpellTower.

It is an inherently (and intentionally) simpler and more limited game, and there may be scoring limits for even the best players.

But it has the nagging replay quality of gems like Threes! and Drop7, with the added advantage of each game taking way less time.

Or perhaps the added disadvantage when you've played 27 games in a row, figure you can get away with 'just one more', and the dawn chorus feels more like local birds have drum-kits, such is the state of your frazzled mind.