If you somehow managed to miss out on Half-Life 2 and its two episodic sequels, there's now a perfect excuse to catch up. They've been remastered for NVIDIA's SHIELD Android TV, a mighty 4K set-top box that doubles up as a powerful HD gaming system, and the final instalment in the series, Episode 2, has just been released in fine-looking 60fps 1080P, perfect for some big-screen first-person shooting.

Picking up where Episode 1 left off – with stoic science hero Dr Gordon Freeman trapped on a derailed train – Episode 2 quickly gets you back into the action and rarely lets up, as once again you take arms against the sinister Combine that now rules the Earth. If you've played the previous games in the series – and if you're not then you should really go back and at least play Half-Life 2 and Episode 1 so that you're up to date with the story – then you'll immediately feel at home as Alyx Vance hands Gordon his gravity gun and they set off for White Forest to meet up with the resistance forces.

Most of the enemies you'll encounter in Episode 2 are thoroughly familiar – an assortment of alien monsters and human soldiers working for the Combine – but Episode 2 introduces a few new adversaries along the way. The antlions from Half-Life 2 and Episode 1 are back again, and one section of the game requires you to infiltrate an antlion colony, where not only will you encounter antlion grubs – oversized glowing maggots that are harmless but irresistibly squishy – but also thoroughly dangerous worker antlions: pale specimens that will spit acid at you, and which explode in a burst of acid as they die, so be sure to kill them from a safe distance.

As you reach the centre of the colony you'll also come up against an antlion guardian: a king-size breed that will mess you up a treat, given half the chance. You're under orders to not kill it on your first encounter, but later on you get the opportunity to take it down, and it's quite a fight; your best bet is to use the gravity gun to launch explosive canisters and barrels at it, rather than waste ammunition on its armoured hide.

Similarly resistant to gunfire are Episode 2's other new enemy, the Hunters. Imposing eight-foot tripods that fire exploding flechettes, they're aggressive and they'll work in packs to wipe you out. The first time you come across one you're powerless to do anything as it demonstrates its vicious abilities, so it's particularly intimidating to finally face more of them in combat.

Fighting Hunters is made easier by Episode 2's more open levels; rather than face them down in a claustrophobic interior, you instead take them on outdoors, with plenty of room to get away, find cover and locate something explosive to fire at them. Much of Episode 2 takes place in more rural locations than previous instalments; plenty of rolling countryside that hints at being somewhere in Russia or Scandinavia and provides a welcome contrast to the browns and greys of earlier games.

This open countryside plays host to Episode 2's climactic battle, an epic fight against a battery of Striders, best described as the Hunters' much bigger brothers. Your task is to stop them attacking and destroying the resistance base at White Forest; the only problem is that they're completely invulnerable to conventional weapons, meaning that you have to fire big sticky bombs – Magnusson Devices – at them with your gravity gun, then set them off with a well-aimed bullet. Which would be tricky enough on its own, but the Striders are escorted by Hunters that will do their best to destroy the Magnusson Devices – and kill you too.

It's a thrilling – and often gruelling – finale to an unmissable slice of gaming history, and sadly it marks the point at which the Half-Life series came to a premature hiatus. Episode 3 was meant to follow, with plenty of Episode 2's events pointing towards it, including the sighting of a lost Aperture Science research ship and the last-minute death of a major character, but it never materialised. Will the story continue in Half-Life 3? We like to hope so.

Half-Life 2: Episode 2 is now available on Google Play for $7.99. The NVIDIA SHIELD Android TV is also available now, with prices starting at $199.