It's out in JP eShop now, with a free demo to boot :)
任天堂の公式オンラインストア。「ミスタードリラーアンコール ダウンロード版」の販売ページ。マイニンテンドーストアではNintendo Switch(スイッチ)やゲームソフト、ストア限定、オリジナルの商品を販売しています。
ec.nintendo.com
EDIT: The demo contains 1P World Drill Tour, which represents the classical Mr. Driller gameplay.
Here's a quick recap of the other modes:
Drindy Adventure -- Indiana Jones-inspired temple raiding! Escape boulders and spike traps in your quest for Gold! (Note, the air meter mechanic is entirely absent from this mode.)
The Hole of Druaga -- A slower-paced take on Mr Driller, where air (now HP) is only consumed as you drill. Use the items you collect to strategically change and eliminate different block colors, and rescue Princess Mr Driller from the dragon's hole.
Horror Night House -- Use holy water to trap demons in blocks, then bust 'em and collect their jewels. Like Drindy, this one completely forgoes the whole air meter mechanic.
Star Driller -- Mr Driller in space! Look out for comets and meteors, and collect power-ups to reduce gravity, increase movement speed, etc. But watch out for those wormholes!