Crimson: Steam Pirates is a turn-based naval combat game from the fine folks at Harebrained Schemes. It's available both on the Apple App Store and on the Chrome Web Store, so it's playable on the PC. It's an enjoyable game, but I'd really like to see a more full-featured sequel.
As you might have guessed from the game title, there is a steampunky theme to the game, but if you prefer, you can think of it as alt-history pulp action. You take the role of a pirate captain, set loose in the Caribbean with a colorful crew and a fantastic array of vessels and weapons, including steam-powered dreadnoughts, airships, and lightning guns. For each mission, you are given a few ships, a few officers, and a few mission objectives, and your end-of-mission score is based on how many objectives you completed, how much loot you collected, and how many targets you knocked out.
Actual gameplay is simple: during each turn, you plan out the movement of each vessel under your command. (Anyone who's played Steambirds will find the movement system familiar.) You don't choose firing targets; your ships will automatically fire at any enemy vessels that move into their firing arcs. You do get to choose a special ability for each of your ships to use, which include such abilities as "fire faster" or "move faster" or "repair damage". Each ship can use one special ability a turn, and when an ability is used, it must recharge for a fixed number of turns before it can be used again.
You can also attempt boarding actions, by using the appropriate special ability and then bringing your ship in contact with a chosen enemy ship. The boarding action occurs in three waves: you may designate which of your officers (each with a different combat strength rating) to send out in each wave. If your total strength in a wave is sufficient to defeat the enemy officers in that wave, you win the wave. You must win all three waves to win the boarding action. A successful boarding action gives you control of the enemy vessel, so long as you transfer at least one of your officers to that vessel. Each officer grants one or more special abilities to the ship that officer is in, so you need to think about which abilities are best placed on which vessels.
Overall, I found the difficulty level fairly low. Out of the first eight missions, I won seven on the first try, and had to run the eighth mission twice. The simple strategy of "keep your ships grouped together, keep the enemy in your firing arcs, and use your special abilities often" was sufficient to overcome every challenge.
The first eight missions of Crimson: Steam Pirates are free to play, and took me about two hours to get through. There are two other mission packs available to purchase, each with eight more missions and each costing $2 USD. So if you buy into the whole package, that's $4 for six hours of entertainment. (If the add-on missions are more difficult or lengthy than the first eight, then your play time might be even longer.) Not a bad deal for a solid, if simple, game in my opinion.
What I'd really like to see is a sequel that allows you to choose which ships to deploy on each mission, and to choose the weapons and officers to assign to each ship. This would add some strategic depth as well as some replayability ("I wonder if I could beat that mission using entirely airships...").
As for the story in the game, it's nothing special or memorable, though I expect it would be challenging to develop a deep story with nothing more than a paragraph of narrative at the beginning and end of each mission. More impressive is the collection of lore about the world of Crimson, posted at the Hairbrained Schemes site. There's a timeline of significant events, lists of notable places, persons, and technology, and a quick sketch of the political situation. There's more than enough information here for a solid roleplaying campaign. Once again, I'd love to see a sequel that provides a deeper exploration of the world.
Overall I recommend it: it's turn-based strategy, it's easy to learn and to play, and the art and style bring back fond memories of the alt-history pulp action of Crimson Skies (it's probably safe to say that the similarity is deliberate). For a total price of zero dollars for the first eight missions, it's certainly worth a look.