Every year, the Alcatraz Bash gives promising Belgian bands the opportunity to earn a place on the festival line-up, and this year Encounters are one of the success stories. The modern metal outfit secured their place by winning one of the competition’s semi-finals, earning themselves the chance to open the final festival day. Their music blends metalcore, djent, electronic elements and industrial influences into a contemporary sound that combines heavy breakdowns with melody and atmosphere.

Following the release of their debut album Wide Asleep in 2025 and the single Affliction earlier this year, Encounters arrive at Alcatraz with clear momentum behind them. Opening a festival stage is never an easy task, but it’s also one of the best opportunities to win over a brand-new audience. If you’re planning to arrive early on Sunday, they’re a band well worth catching.

If subtlety isn’t what you’re looking for, Steengruis have you covered. The Flemish grindcore outfit have been making unapologetically loud, fast and humorous extreme metal since 2006, building a loyal following through a combination of grindcore, death metal and an irreverent sense of humour. Their songs switch freely between Dutch and French while never taking themselves too seriously, creating a live experience that’s as entertaining as it is relentless.

This year also marks two milestones for the band. They celebrate twenty years together while making their Alcatraz debut, bringing one of Belgium’s longest-running underground grindcore acts to the festival for the very first time. Expect short songs, relentless energy and plenty of smiles along the way.

Sunday also marks the Alcatraz debut of Turpentine Valley, another Belgian band proving just how expressive instrumental heavy music can be. The trio from East Flanders have spent the past decade refining a sound that balances towering walls of distortion with moments of restraint and atmosphere. Rather than rushing towards the next heavy section, Turpentine Valley allow their songs to unfold patiently, creating a natural tension that makes every crushing climax hit that much harder.

Released earlier this year, Veuel continues that approach while also maintaining one of the band’s most distinctive trademarks: using words from the local East Flemish dialect as album and song titles. It’s a subtle detail that gives the band an identity that’s unmistakably their own, and their first appearance at Alcatraz feels like a well-earned next step.

For those who enjoy getting completely absorbed in instrumental music, Hemelbestormer should be high on the list for Sunday. Formed in 2012, the Limburg quartet have carved out their own place within the post-metal landscape by combining crushing doom riffs, atmospheric post-rock and subtle black metal influences into expansive instrumental compositions. Without a vocalist to guide the listener, the music itself tells the story, often revolving around themes of space and the unknown.

Their latest album, The Radiant Veil, released through Pelagic Records in 2025, continues that fascination by exploring our solar system through the lens of ancient Etruscan mythology. It’s another ambitious chapter in a discography that has steadily established Hemelbestormer as one of Belgium’s most distinctive instrumental heavy bands.